Zimbabwe's 91-year-old President Robert Mugabe told state television that his wife Grace, a rising political star in the ruling party, is not the power behind his throne.

Mugabe, the only leader his country has known since independence from Britain in 1980, will be in the resort town of Victoria Falls on Saturday where his ZANU-PF party is planning $1 million birthday celebration with thousands of supporters.

Grace, a former typist in Mugabe's office before theymarried, was hoisted into the top echelons of ZANU-PF last December after attacking former vice president Joice Mujuru, who was later fired by the veteran leader.

Political analysts and local media have said Grace, who now sits next to Mugabe at meetings of the ruling party's politburo, wields considerable influence over one of the most controversial leaders in Africa.

“She is not the power behind the throne,” Mugabe said in an interview with ZBC TV on Thursday night. “Why should they think that because of what she has done she is now the power?”

Until her demotion, Mujuru was seen as the most likely to take Mugabe's place when he dies or retires.

Mugabe, who has in the past attributed his long life to the will of God, said a good diet was key to his health. He plans to run in the 2018 election, his last under a new constitution, when he will be 94.

Mugabe denies media reports he suffers from prostate cancer and says his frequent trips to Singapore are for eye problems.

“I eat well, not filling my stomach, eating foodstuffs that I believe sustain one most. You must eat well, and really not go for food because it's attractive,” said Mugabe, who turned 91 on Feb. 21.